An electronic element in an electronic device, such as, for example, a central processing unit, usually produces a large amount of heat during operation thereof and accordingly has a raised temperature. In the case the produced heat is not properly dissipated, it will cause overheat and unstable operation of the electronic element to result in stop or even crash of the whole electronic device. Meanwhile, with the constantly increased operating speed of various kinds of electronic elements, the heat produced by them also largely increases. Thus, the heat sink employed in the electronic device for dissipating the produced heat becomes more and more important.
Conventional heat sinks can be classified into two major types, namely, an integrally formed heat sink and an assembled heat sink formed from a plurality of stacked radiating fins. The radiating fins are bent at respective one edge to form connecting sections, which are welded to a base so that the radiating fins are connected to the base to form the heat sink. The welding of the radiating fins to the base results in complicated assembling procedures and does not meet the current requirement for environmental protection. Therefore, there were manufacturers who provide an insertion-type heat sink by inserting the radiating fins onto the base. The conventional insertion-type heat sink 1 usually includes a base 10 and a plurality of radiating fins 11. The base 10 is formed on one face with a plurality of grooves 101, into which the radiating fins 11 are inserted. According to the currently available technical skills, there are generally two ways for fixedly connecting the radiating fins 11 to the base 10. As shown in FIG. 1A, the first way is to directly weld the radiating fins 11 to the base 10, and in this way the welding will result in increased manufacturing cost. The second way is shown in FIG. 1B, in which the connecting sections 111 of the radiating fins 11 are first loosely fitted in the grooves 101 formed on the base 10, and then a tool 12 is used to punch against areas on the base between any two adjacent grooves 101, such that open tops of the grooves 101 are deformed to clamp on the connecting sections 111 of the radiating fins 11 in a tight-fit manner, as shown in FIG. 1C. However, while the deformed open tops of the grooves 101 clamp on the connecting sections 111 of the radiating fins 11 in a tight-fit manner, all other portions of the connecting sections 111 below the deformed open tops of the grooves 101 are still inserted in the grooves 101 in the loose-fit manner. Therefore, the connection of the radiating fins 11 to the base 10 in the second way tends to cause thermal resistance and easy separation of the radiating fins 11 from the grooves 101.
Accordingly, the conventional heat-dissipation units have the following disadvantages: (1) requiring increased manufacturing cost; (2) tending to have a deformed base; and (3) having a relatively unstable structure.
It is therefore tried by the inventor to develop an improved heat-dissipation unit and a method of manufacturing same, so as to overcome the problems in the prior art.